"Many do not only fear their arrival but fear whether all of them would leave. This is the question raised by not just the opposition, not just the citizens but I think also by (Belarusian President) Alexander Lukashenko who also seems concerned," Belarusian opposition figure Anatoly Lebedko said at a meeting at the Lithuanian parliament on Tuesday.

Russia reportedly intends to bring about 4,000 train cars full of military equipment and weaponry for the joint war games to take place in Belarus this fall.

In Lebedko's words, this is not the biggest figure. According to information available to him, about 6,000 cars with military equipment had come from Russia in 2009. On the other hand, the opposition activist noted that this was before the annexation of Crimea and the developments in Ukraine.

Officials have said earlier Zapad war games provided training to occupy the southern part of Lithuania, thus blocking the only land route for NATO countries to the Baltic states. The last exercise Zapad took place in 2013. Moscow and Minsk said it involved about 10,000 troops.